I’ve been in and out of HJ a couple of times.
Rode as a junior in the late 60’s and early 70’s. Quit for about ten years for school. Came back and did HJ mostly local with some jumpers at bigger shows and evented a bit. Full chaps were still a thing but more fitted and custom. Tall boots were more fitted and taller. More people wore helmets. There were still a lot of TB’s when I started back, but that dwindled over time. Lots of people still kept horses in backyards and rode to lessons and, sometimes, even shows. Navajo saddle pads were still in vogue. My last few years as a junior, outfits got really wild (one person even had a yellow coat with black buttons!) but all was back to navy and black when I returned.
Had a hiatus to dressage for a few years when my eventing prospect liked the rectangular ring better than leaping over things. Came back when the dressage prospect preferred jumping. In the meantime, boots got zippers, helmets were mandated, there were a LOT of warmbloods, and more people were in programs and had grooms. But we still wore wool coats and cotton shirts. Breeches got better (no more buttons or zippers at the bottom). People were paying more attention to footing. At some point you could no longer be asked to trot or canter directly into the ring as part of an eq test. The variety of bits and mouthpieces (hello bits with two joints) expanded.
Had five or so years of horses with issues and not much showing. When I came back, coats were stretchy. Shirts were also stretchy, breathable, and had lost the chokers. There were more grooms and fewer true local shows, though we’re relatively lucky in my immediate and greater area. Boots were more sock-like.
Cue a few more years of horse issues and…mesh jackets, air vests, continued footing improvements, hunters and eq horses getting really expensive.